Method for making a reservoir

ABSTRACT

The invention relates to a process for manufacturing a water reservoir with an inlet and an outlet which are compressively sealingly engaged with the water reservoir tank by utilizing the latent heat of extrusion of the extrudate to bond with the exterior surfaces of the inlet and outlet profiles.

TECHNICAL FIELD

This invention relates generally to a process for making a reservoir byusing the latent heat of extrusion of an extrudate to sealingly engageingress and egress tubes, specifically a water reservoir storage tankfor use in a refrigerator, primarily to cool water for use in bothdrinking outlets and ice cube makers. More specifically, the inventionrelates to a reservoir volume which includes a main body reservoirutilizing an extruded profile into which are added ingress and egresslines utilizing extruded profiles and which are sealingly engaged intothe reservoir volume by compression molding using the latent heatpresent in the reservoir extrudate.

BACKGROUND OF THE INVENTION

It is known to provide dispenser units in the front doors ofrefrigerators in order to enhance the accessibility to ice and/or water.Typically, such a dispenser unit will be formed in the freezer door of aside-by-side style refrigerator or in the fresh food or freezer door ofa top mount style refrigerator. In either case, a water line will beconnected to the refrigerator in order to supply the needed water forthe operation of the dispenser. For use in dispensing the water, it iscommon to provide a water tank within the fresh food compartment to actas a reservoir such that a certain quantity of the water can be chilledprior to being dispensed.

Most dispenser equipped refrigerators available on the market todayincorporate blow molded water tanks which are arranged vertically inlower sections of the fresh food compartments. More specifically, such awater tank is typically positioned behind a crisper bin or a meat keeperpan within a bottom section of the fresh food compartment so as to besubjected to the cooling air circulating within the compartment. Ofcourse, locating the water tank in the bottom section of the fresh foodcompartment reduces the permissible size of the crisper bin and/or meatkeeper. In addition, since the tank is not an aesthetically appealingfeature of the refrigerator, it is generally hidden from view by a sightenhancing cover.

There are at least two commonly employed methods for attaching ingressand egress tubes to the water reservoir. One approach involves theinjection molding of threaded flights of screws for use with acorrespondingly threaded nut and ferrule or O-ring combination. Thisapproach is illustrated in U.S. Pat. Nos. 3,511,415 (to Crowe); or3,982,406 (to Hanson et al.). Another approach involves friction fittingof an elastic plastic tube over an injection molded inlet and/or outlet,with optional molded ribs. This approach is illustrated in U.S. Pat.Nos. 4,739,629 (to True); 5,315,845 (to Lee); or 6,079,221 (to Senner).In order to minimize leaks with this type of connection, adjustable hoseclamps are often used in conjunction with the friction fit of theelastic plastic hose.

Based on the above, there exists a need in the art for an improvedmethod of manufacturing the water reservoir which minimizes thepotential for leakage and which additionally minimizes the amount ofmanual intervention required to fasten the ingress (inlet) and egress(outlet) profiles of the water reservoir.

SUMMARY OF THE INVENTION

Accordingly it is an object of the invention to provide an attachmentmethod in the manufacture of a water reservoir which creates amaterial-to-material bond at the ingress and egress attachment areas ofthe water reservoir.

It is another object of the invention to provide a method of fabricatinga serpentine-shaped water reservoir which employs compression molding tocreate a material-to-material bond at the ingress (inlet) and egress(outlet) attachment areas of the water reservoir.

It is still another object of the invention to provide a method offabricating a serpentine-shaped water reservoir which employscompression molding in combination with extruded profiles to whichair-core molding technology is applied to create a material-to-materialbond at the ingress and egress attachment areas of the water reservoir.

To the accomplishment of the foregoing and related ends the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andthe annexed drawings setting forth in detail certain illustrativeembodiments of the invention, these being indicative, however, of but afew of the various ways in which the principles of the invention may beemployed.

BRIEF DESCRIPTION OF THE FIGURES

The invention may take physical form in certain parts and arrangementsof parts, a preferred embodiment of which will be described in detail inthe specification and illustrated in the accompanying drawings whichform a part hereof, and wherein:

FIG. 1 is a perspective view of a side-by-side refrigerator with partsbroken away showing a Prior Art reservoir volume with injection moldedconnections for ingress and egress tubes;

FIG. 2 is a side elevational view of a side-by-side refrigerator withthe fresh food compartment door removed to show the Prior Art invention;

FIG. 3 is an enlarged view taken along lines 3-3 of Prior Art FIG. 2;

FIG. 4 is a cross-sectional view taken along lines 4-4 of Prior Art FIG.2;

FIG. 5 is an enlarged perspective view of a portion of the Prior Artwater storage tank;

FIG. 6 is a side elevational view of the Prior Art water storage tankshowing the configuration of the tank in the event water containedtherein is frozen;

FIG. 7 is a front perspective view of a water reservoir of the inventionwith ingress and egress tubes molded thereto;

FIG. 8 is a cross-sectional view taken along lines 8-8 of FIG. 7;

FIG. 8 a is an exploded view of one of the molded tube areas of FIG. 8without insert; and

FIG. 8 b is an exploded view of one of the molded tube areas of FIG. 8with insert.

DETAILED DESCRIPTION OF THE INVENTION

The invention is described with reference to the accompanying figures,which illustrate the best mode known to the inventor at the time of thefiling of the application illustrating the method of forming thereservoir, preferably for transporting liquids although not limited tosuch, with connecting ingress and egress profiles of the invention.

With reference to Prior Art FIG. 1 and FIG. 2, there is shown arefrigerator 10 of the side-by-side type wherein there is a freezercompartment on the left hand side closed by a freezer door 12 and afresh food compartment 14 shown in the figures with the fresh foodaccess door and shelves removed. At the bottom of the fresh foodcompartment 14 is a meat/vegetable pan assembly including twoside-by-side pans 18 and 20 which are covered by a cover 22. Usuallythere is another vegetable pan above the assembly 16 that extends thewidth of the fresh food compartment that would be located in front ofthe water storage tank 26 of the present invention which is secured tothe rear wall 24 of the compartment. That pan has been omitted in orderto see the water storage tank 26. Located at the top of the fresh foodcompartment is a cold air control assembly 28 which the user adjusts toregulate the amount of cold air being introduced from the freezercompartment into the fresh food compartment to keep it at the desiredtemperature.

The household refrigerator shown in the preferred embodiment is of theside-by-side type and has in the outside of the freezer door 12 adispensing compartment 30 wherein the user may obtain ice cubes or coldwater depending upon the selection by pressing one or the other of theactuators 32 or 34. Not shown is a tube connecting the water storagetank 26 to the outlet for dispensing the cold water into a glass held bythe user in the dispensing compartment 30.

With particular reference to FIG. 1 and FIG. 2, the water storage tank26 comprises a serpentine shaped hollow body having a first straightsection 36, a second straight section 38, a third straight section 40,and a fourth straight section 42. These sections are essentiallyparallel to each other as shown in FIG. 2 and the first section 36 hasan inlet 44 at the top end 46 and the fourth section 42 has an outlet 48at the top end 50. The first section 36 is connected to the secondsection by a U-shaped curved section 52 at the bottom end, the secondsection 38 and third section 40 are connected at the top by a U-shapedcurved section 54, and the third section 40 and fourth section 42 areconnected at the bottom by a U-shaped curved section 56. In this PriorArt reservoir configuration, the four straight sections 36, 38, 40 and42 are connected at the top thereof by air flow passageways and as shownin the figures. The first passageway extends from the top 46 of thestraight section 36 to the top U-shaped curved section 54 and isdesignated as passageway 58. Between the top U-shaped curved portion 54and the top end 50 of straight section 42 there is air passageway 60. Inthis particular Prior Art reservoir, these passageways are provided inorder to bleed off any air trapped in the water storage tank so that thewater in the tank may be dispensed in a desirable fashion. It will benoted that the four straight sections 36, 38, 40 and 42 are onlyconnected by the three U-shaped curved sections 52, 54 and 56 and theair flow passageways 58 and 60.

The water storage tank 26 is typically molded from polyethylene plasticmaterial and in molding the storage tank the U-shaped curved sections52, 54 and 56 have the internal curvature area 62, 64 and 66respectively in the shape of a teardrop which can readily been seenhaving a wider radius in each of the internal curvature areas 62, 64 and66 relative to a straight sided reverse curvature. It has been foundthat with this teardrop shape increased surface area is provided in thecurved sections so that in the event water in the tank freezes thematerial forming the internal curvature areas 62, 64 and 66 will stretchsufficient to prevent rupture of the walls of the water storage tank 26.Moreover, as shown in FIG. 6 the second straight section 38 and thethird straight section 40 may separate or diverge from each other in adirection away from the top U-shaped curved section 54 and thus againrelieve the force exerted on the water tank by the frozen watercontained therein.

As shown particularly in Prior Art FIG. 4 and FIG. 5, the lateralcross-sections of the straight sections 36, 38, 40 and 42 may be polygonin shape. When the profile is hexagonal in cross-section, there isprovided a plurality of relatively straight sides so that when the waterin the tank 26 freezes the relatively straight sides will bow outwardlyand approach a circle configuration as viewed in lateral cross-section,again relieving the internal stress caused by the frozen water toprevent rupture of the water storage tank.

The water storage tank 26 in generally secured to the rear wall 24 ofthe fresh food compartment 14 and for this purpose there is providedstorage tank support means 68 which may be in the form of a U-shapedchannel having a base 70 and two spaced apart legs 72 and 74 which legsterminate with an inwardly directed flange 76 and 78 respectively. Thelegs and base form an open ended channel 79 and at the junction of thebase 70 and the legs 72 is a projection 80 which as seen in FIG. 3 isinserted in an opening in the back wall 24 to support the storage tanksupport means 68. The water storage tank 26 has at least one securingmember 82 located at the bottom of at least one U-shaped curved sectionsuch as section 52, which securing member 82 cooperates with the supportmeans 68 to allow relative movement therebetween and to secure the waterstorage tank to the fresh food compartment. As illustrated in the PriorArt reservoir, the securing member 82 is molded in the water storagetank and has a T-shaped cross-section member 84 which slides into thechannel 79 of the storage tank support means 68. As can be seen, theT-shaped member 84 can move back and forth in the storage tank supportmeans 68 thereby providing relative movement between the T-shaped member84 and the support means 68.

In the Prior Art water reservoir illustrated, there are two of theseassemblies at the bottom of the water storage tank 26, one located atthe bottom of the U-shaped curved section 52 and another at the bottomof the U-shaped curved section 56. The top of the water storage tank 26is also secured to the rear wall 24 of the fresh food compartment bymeans of a clip 86 having one end fastened by suitable means to the rearwall 24 and the opposite end having a U-shaped portion 88 which receivestherein the upper securing member 82 so that the securing member 82cooperates with the U-shaped section 88 to prevent movement of the waterstorage tank relative to the rear wall 24. The securing member 82 at thetop of the water tank is also molded along with the water tank and isformed in the U-shaped curved section 54. It will be noted that thePrior Art water storage tank 26 may have two sections, one made up ofstraight sections 36 and 38 and one made up of straight sections 40 and42. With this structural arrangement the two sections may be physicallymoved away from each other at the bottom thereof. This spread apartposition is shown in FIG. 6. In the event water in the water storagetank 26 freezes, these two sections can spread apart at the bottom tohelp relieve the internal stresses caused by the frozen water and alsohelp to prevent rupture of the storage tank. This movement of the twosections is permitted because of the relative movement allowed by thecooperative arrangement between the securing member 82 and the storagetank support means 68 at the bottom of the storage tank.

FIG. 7 and FIG. 8 illustrate one embodiment of the reservoir 100,preferably a water reservoir of this invention, preferably for use inrefrigerator chilled water dispensers as well as ice cube makers. Waterreservoir 100 includes a serpentine main body containing a plurality ofessentially parallel profile volumes, 110, 112, 114, 116, 118 which arepreferably cylindrical in shape, although any polygon shape incross-section is applicable as evidenced by the polygon-shape of thePrior Art in FIGS. 4-5. While five (5) interconnected volumes are shownin the figure, there is no need to limit the scope of the invention toany particular number, and the number of regions or sections is simply ameasure of the capacity of the reservoir. In general, a greater numberof interconnected cylindrical volumes is preferred over one largecylindrical volume in that the water cooling rate is slower for largervolumes due to the decreased aqueous surface area which is in directcontact with the chilled walls of the volume, thereby requiringincreased time to cool the water to the desired temperature.

The volumes have an expanded middle section and a pair of oppositelynecked regions 132, 134, 136, 138, 140, 142, 144 and 146 at each end ofthe middle section. Each necked region is interconnected to each otherby generally U-shaped bends 122, 124, 126 and 128. The first 110 andlast 118 volume also have initial 130 and terminal 148 necked regionswhich initiate and terminate at sealing regions 154 and 156 respectivelywith inserted ingress 158 and egress 160 profiles, preferablycylindrical tubes.

Water reservoir 100 is made by initially extruding an initial profile,preferably essentially cylindrical as illustrated in FIGS. 7-8 b As theprofile is extruded, it can either be cut to a predetermined length, andtransitioned into a heating oven, or transferred immediately into amold. In order to manufacture the serpentine profile illustrated in thefigures, the mold will need to have a corresponding serpentineconfiguration. The mold internal dimensions are of similar diameter tothat of the extrudate profile for the U-shaped bend regions, andpreferably are slightly larger. The diameter of the middle section ofthe mold will be larger than that of the extudate. In the processembodiment where the extrudate is transitioned immediately into themold, an operator manually shapes the extrudate to follow the serpentinepath of the mold. After positioning of the extrudate, the operatorinserts at least a portion of inlet profile 158 and outlet profile 160into the beginning and end apertures of the extrudate profile. The depthof the insertion defines the sealing region of the exterior surface ofthe inserted profile with the interior surface of the extrudate. Theoperator seals one profile end and connects the other profile end to asource of pressure, typically compressed air. The mold is closed andpressure applied to expand the profile within the mold to conform to themold cavity dimensions. While the option of sealing one end of theprofile is described above, it is envisioned that an operator may chooseto connect both profile ends to a source of pressure and expansion ofthe extrudate is effected from both ends. It is further envisioned thatvacuum could be applied to the exterior of the extrudate in the mold toassist in the expansion process of the extrudate or used as the solemeans of effecting the extrudate expansion within the mold.

In another embodiment of the invention, namely the process whereby theinitial extrudate is transitioned into a heating oven, the extrudateprofile is heated or maintained at a temperature at which the profile ismalleable, yet will not collapse upon itself. This extrudate profile istransferred into a mold having a cavity of the desired geometry and theprocess is repeated in a manner similar to that described above.

As illustrated in FIG. 8 a and FIG. 8 b, depending upon the materialcomposition of the extrudate, and the temperatures involved, it is anoptional process variation to have an insert 162 positioned at each endof the inlet profile 158 and outlet profile 160. This insert may bemetallic or polymeric and is used to insure that at least a portion ofthe heated portion of the inserted profile remains open for liquid toflow therein. The need for this insert is known to those skilled in theart depending upon the mold temperatures and/or the extrusiontemperature and the interaction therebetween.

By inserting the inlet and outlet tubes into the heated serpentineprofile, it is possible to obtain a material-to-material bondtherebetween by a judicious choice of the composition of each. There areseveral means by which this bond may be effected. One of the simplestprocedures is to insure that at least a component of the inlet andoutlet profiles and that of the reservoir main body polymer profile isthe same. Alternatively, it would be possible to insure that at least aportion of the polymer composition of the inlet and outlet profiles andthat of the reservoir main body polymer profile is sufficiently similaror compatible so as to permit the melt fusion or blending or alloying tooccur at least in the interfacial region between the exterior surfacesof the inserted profiles and the contacting interior region of theextrudate main body polymer profile. Another manner in which to statethis would be to indicate that at least a portion of the polymercompositions of the inserted profiles and main body are miscible.

While the precise composition of the inserted profiles and main bodyprofile polymer are not required to be of any specified composition, ingeneral, there are several guidelines which are applicable in thepractice of this invention. It is of course, recognized that the preciseoperating conditions utilized in the sealing process are well-known inthe art and are specific to each polymer combination. It is well withinthe skill of the art to determine the applicable conditions which willresult in the appropriate degree of bonding required for the intendedend-use application, which is dependent upon the required pressure thatthe final water reservoir will be subject to. Shorter cycle times willbe achieved with higher mold temperatures and vice-versa. Similarconsiderations will be applicable dependent upon the thickness of theparts to be sealed together. The inserted plastic profiles can be athermoplastic or a thermoset The key is that the overlapping regions ofthe main extrudate profile with that of the inserted profile must becapable of forming a leak-proof bond, either chemical or physical.

The above conditions may be met by using polymer compositions which havediffering softening points or may involve the use of two compositionswhich have the same softening point, but which are of differentthickness. Through manipulation of the time, temperature and pressureconditions experienced during the compression molding operation, theinserted profile will not experience melt flow, even though it had asimilar softening point or range. It is also possible that through theincorporation of various additives in the polymeric compositions, e.g.,glass fibers, heat stabilizers, anti-oxidants, plasticizers, etc., thesoftening temperatures of the polymers may be controlled.

In a preferred embodiment of the invention, the composition of the mainbody of the water reservoir extrudate polymer will be such that it willbe capable of at least some melt fusion with the composition of theinserted plastic profile, thereby maximizing the leak-proofcharacteristics of the interface between the exterior of the insertedprofile and the interior of the main body extrudate. There are severalmeans by which this may be effected. One of the simplest procedures isto insure that at least a component of the plastic conduit and that ofthe overmolded polymer is the same. Alternatively, it would be possibleto insure that at least a portion of the polymer composition of theplastic conduit and that of the overmolded polymer is sufficientlysimilar or compatible so as to permit the melt fusion or blending oralloying to occur at least in the interfacial region between theexterior of the plastic conduit and the interior region of theovermolded polymer. Another manner in which to state this would be toindicate that at least a portion of the polymer compositions of theplastic conduit and the overmolded polymer are miscible.

Depending on the equipment available, the end application requirements,cost factors, etc., the starting extrudate material will be different.For many applications, polyolefins, e.g., polypropylene, polyethylene,etc., are preferred. Depending on the application, the polyethylene maybe crosslinked, or partially crosslinked. The crosslinking of thepolyethylene may be effected in two stages, with an initial degree ofcrosslinking being less than 50%, preferably less than 35%, followed bypost-extrusion processing, and ultimately a second degree ofcrosslinking raising the final degree of crosslinking to at least 60% orhigher, often to 85%. Cost usually decides which crosslinking methodneeds to be used to provide a given quality of tubing. The benefit ofcrosslinking the polyethylene subsequent to the fabrication stepsdescribed in the application is that a chemical and/or thermal materialbond is formed during the compression molding processes, resulting in astronger product. However, there may be applications where this highdegree of bonding is not essential, thereby permitting the use ofpreviously crosslinked material during the fabrication procedure.Previously crosslinked material has a much better hot melt strengthsince the crosslinking gives it more structure, and making formingeasier. However, the crosslinked material will not chemically bond toitself even when heated to the clear state. The material in the formedends is not completely sealed upon itself, but molded in place withpressure.

Crosslinking can of course, be accomplished in many different ways.Crosslinking can be performed during the extrusion process, e.g., byEngel process, or post-extrusion, e.g., by a silane process or aperoxide process or combinations thereof wherein some crosslinkingoccurs during the extrusion step and is completed in a hot bathpost-extrusion step. Each process has a crosslinking catalyst thatcauses the polymer to crosslink when certain temperature and pressureare used. One additional way to crosslink is to use radiation. In thismethod, extruded tubes are passed under a radiation unit and theexposure causes crosslinking. It usually is more economical to radiatestraight tubes since the economics revolve around how many parts willfit on a cart that rolls under the beam. However, this does notrepresent the only embodiment contemplated within the invention. It isenvisioned that under some circumstances, it would be appropriate tocrosslink the final product. Crosslinking of plastics, particularlypolyolefins, most preferably polyethylene is desirable in that itremoves any odor and/or taste-imparting additives which may be leachedfrom the plastic when in contact with water.

Therefore, what has been described above may be generalized as theability to fabricate a plastic part by the combination of severalprocessing technologies in sequence, namely extrusion followed by acombination of compression molding and air-core molding, the latter twomethodologies being employed either essentially simultaneously orsequentially. Plastic profiles are extruded with subsequent insertioninto a mold having a cavity of desired internal configuration. Theheated and/or malleable extrudate is positioned in the mold followed byinsertion of previously extruded profiles which are inserted into thebeginning and end apertures of the main extrudate body. One end of aninserted profile is sealed while the remaining open end of the otherinserted profile is connected to a pressurized source of gas. The moldis closed and pressure applied to expand the main extrudate body to fillthe mold cavity. Through the application of heat and pressure about thesealing regions of the inserted profiles for an appropriate amount oftime depending upon the thickness, composition and either latent heat ofthe main extrudate or applied heat in the mold, an essentiallyleak-proof seal is effected. The pressure is released and reservoirassembly removed from the mold.

Therefore, what has been described above is a process for making areservoir comprising the steps of: positioning a hollow extrudate at afirst temperature (essentially at the extrusion temperature of theextrudate or slightly below) having a profile into a mold with a cavity,the mold cavity having at least one cavity dimension which is largerthan a corresponding dimension of the extrudate profile; the extrudatehaving a first and second opening, each opening positioned at an end ofthe extrudate; inserting one end of a hollow first polymeric profile ata second temperature (often approximately room temperature), the secondtemperature being less than the first temperature into the first openingof the extrudate, the end of the first profile being dimensionallysmaller than the first opening of the extrudate; inserting one end of ahollow second polymeric profile at a third temperature (and oftenapproximately room temperature), the third temperature being less thanthe first temperature into the second opening of the extrudate, the endof the second profile being dimensionally smaller than the secondopening of said extrudate; sealing or affixing at least one source ofpressurized gas to at least one non-inserted end of either the first orsecond profile; closing the mold and pressurizing said hollow extrudateby the application of pressure through at least one non-inserted end sothat the hollow extrudate expands to fill said at least one cavitydimension through the application of internal pressure or externalvacuum and form forming at least one expanded section in the extrudateand compressively seal an exterior surface of the two inserted ends ofthe first and second hollow profiles with an interior surface of saidends of the extrudate using the latent heat within the extrudate at thefirst temperature and forming a reservoir; releasing the pressure and/orvacuum; and removing the reservoir from said mold.

It should be recognized that while the positioning of the waterreservoir has been illustrated to be essentially vertical in placementwithin the refrigeration unit, there is no need to limit the reservoirto this orientation. It is envisioned to be within the scope of thisinvention that any and all orientations which fit within the appropriatelocation of the unit are within this invention. Reservoir orientationplays no role in this invention. It is also envisioned that thereservoir described hereinabove could be used for applications otherthan the transport of liquids, namely gaseous transport. When used forgases, filter material may optionally be included, e.g., molecularsieves, diatomaceous earth, etc.

In the foregoing description, certain terms have been used for brevity,clearness and understanding; but no unnecessary limitations are to beimplied therefrom beyond the requirements of the prior art, because suchterms are used for descriptive purposes and are intended to be broadlyconstrued. Moreover, the description and illustration of the inventionis by way of example, and the scope of the invention is not limited tothe exact details shown or described. This invention has been describedin detail with reference to specific embodiments thereof, including therespective best modes for carrying out each embodiment. It shall beunderstood that these illustrations are by way of example and not by wayof limitation.

1. A process for making a reservoir comprising the steps of: (a)positioning a pliable hollow extrudate into a mold with a serpentinecavity at a first temperature, said extrudate having a profile incross-section, (i) said serpentine cavity having at least one cavitydimension which is larger than a corresponding dimension of saidextrudate profile, said serpentine cavity having at least twoessentially parallel expanded middle sections and at least a pair ofoppositely necked regions, each necked region interconnected bygenerally U-shaped bends; (ii) said extrudate having a first and secondopening, each opening positioned at an end of said extrudate; (b)inserting one end of a hollow first polymeric profile at a secondtemperature, said second temperature being less than said firsttemperature, into said first opening of said extrudate, said end of saidfirst profile being dimensionally smaller than said first opening ofsaid extrudate; (c) inserting one end of a hollow second polymericprofile at a third temperature, said third temperature being less thansaid first temperature, into said second opening of said extrudate, saidend of said second profile being dimensionally smaller than said secondopening of said extrudate; (d) sealing one non-inserted end incombination with affixing at least one source of pressurized gas to saidother non-inserted end of either said first or second profile; (e)closing said mold and pressurizing said hollow extrudate by theapplication of pressure through said other non-inserted end having atleast one source of pressurized gas affixed thereto so that said hollowextrudate expands to fill said at least one cavity dimension, to form atleast one expanded section in said extrudate, and to compressively sealan exterior surface of said two inserted ends of said first and secondhollow profiles with an interior surface of said ends of said extrudateusing said latent heat within said extrudate at said first temperatureand forming a reservoir, wherein said reservoir includes said first andsecond polymeric profiles; (f) releasing said pressure; and (g) removingsaid reservoir from said mold.
 2. The process of claim 1 wherein saidlatent heat from said extrudate is sufficient to permit positioning ofsaid hollow extrudate profile into said mold without the application ofexternal heat.
 3. The process of claim 1 which further comprises a stepof crosslinking said extrudate.
 4. The process of claim 3 wherein saidextrudate and said first and second profiles are polyolefins.
 5. Theprocess of claim 4 wherein said polyolefin is polyethylene.
 6. Theprocess of claim 3 wherein said step of crosslinking is effected byexposure to an electron beam.
 7. The process of claim 1 wherein saidhollow extrudate is at least partially crosslinked before insertion ofsaid first and second profiles.
 8. A process for making a reservoircomprising the steps of: (a) positioning a pliable hollow cylindricalextrudate into a mold with a serpentine cavity at a first temperature,said extrudate having a profile in cross-section, (i) said serpentinecavity having at least one cavity dimension which is larger than acorresponding dimension of said extrudate profile, said serpentinecavity having at least two essentially parallel expanded middle sectionsand at least a pair of oppositely necked regions, each necked regioninterconnected by generally U-shaped bends; (ii) said extrudate having afirst and second opening, each opening positioned at an end of saidextrudate; (b) inserting one end of a hollow first cylindrical polymericprofile at a second temperature, said second temperature being less thansaid first temperature, into said first opening of said extrudate, saidend of said first profile being dimensionally smaller than said firstopening of said extrudate; (c) inserting one end of a hollow secondcylindrical polymeric profile at a third temperature, said thirdtemperature being less than said first temperature, into said secondopening of said extrudate, said end of said second profile beingdimensionally smaller than said second opening of said extrudate; (d)affixing at least one source of pressurized gas to each non-inserted endof said first and second profile; (e) closing said mold and pressurizingsaid hollow extrudate by the application of pressure through at leastone end so that said hollow extrudate expands to fill said at least onecavity dimension, forming at least one expanded section in saidextrudate, and compressively sealing an exterior surface of said twoinserted ends of said first and second hollow profiles with an interiorsurface of said ends of said extrudate using said latent heat withinsaid extrudate at said first temperature, thereby forming a reservoir,wherein said reservoir includes said first and second polymericprofiles; (f) releasing said pressure; and (g) removing said reservoirfrom said mold.
 9. The process of claim 8 wherein said latent heat fromsaid extrudate is sufficient to permit positioning of said hollowextrudate profile into said mold without the application of externalheat.
 10. The process of claim 8 which further comprises a step ofcrosslinking said extrudate.
 11. The process of claim 10 wherein saidextrudate and said first and second profiles are polyolefins.
 12. Theprocess of claim 11 wherein said polyolefin is polyethylene.
 13. Theprocess of claim 10 wherein said step of crosslinking is effected byexposure to an electron beam.
 14. The process of claim 8 wherein saidhollow extrudate is at least partially crosslinked before insertion ofsaid first and second profiles.
 15. The process of claim 8 which furthercomprises the step of adding an insert into at least one of said firstand second profiles.
 16. A process for making a water reservoircomprising the steps of: (a) extruding a hollow polymeric profile at anextrusion temperature; (b) transferring said extrudate into a serpentinemold with a cavity at a temperature where said extrudate is formable,(i) said serpentine cavity having at least one cavity dimension which islarger than a corresponding dimension of said extrudate profile, saidserpentine cavity having at least two essentially parallel expandedmiddle sections and at least a pair of oppositely necked regions, eachnecked region interconnected by generally U-shaped bends; (ii) saidextrudate having a first and second opening, each opening positioned atan end of said extrudate; (c) compressively sealing two hollow polymericprofiles essentially at room temperature in said openings of saidextrudate at opposed ends of said extrudate using latent heat of saidextrudate; (d) expanding at least one portion of said extrudate by theapplication of a means for expanding to said extrudate; (e) releasingsaid means for expanding; and (f) removing said reservoir, includingsaid first and second polymeric profiles, from said mold.
 17. Theprocess of claim 16 wherein said latent heat from said extrudate issufficient to permit positioning of said hollow extrudate profile intosaid mold without the application of external heat.
 18. The process ofclaim 17 which further comprises a step of crosslinking said extrudate.19. The process of claim 18 wherein said extrudate and said first andsecond profiles are polyolefins.
 20. The process of claim 19 whereinsaid polyolefin is polyethylene.
 21. The process of claim 18 whereinsaid step of crosslinking is effected by exposure to an electron beam.22. The process of claim 16 wherein said hollow extrudate is at leastpartially crosslinked before insertion of said first and secondprofiles.
 23. The process of claim 16 which further comprises the stepof adding an insert into at least one of said polymeric profiles. 24.The process of claim 16 wherein said means for expanding is internalpressure.
 25. The process of claim 16 wherein said means for expandingis external vacuum.
 26. The process of claim 16 wherein said means forexpanding is internal pressure and external vacuum.